Fuel feeding and injection apparatus for oil-burning engines



' sept- 24, 1946- c. cUMMlNs 2,408,298

FUEL FEEDING ANDINJECTION APPARATUS FOR OiL BURNING ENGINES Filed April 26, 1943 9 Shets-Sheet 1 v INVENTOR. 1495 s s: j I

Spt. 24, 1946. c. CUMMINS FUEL FEEDING AND INJECTION APPARATUS FOR OIL BURNING ENGINES- Filed April 26,1945 '9 Sheets-Sheet 2 Sept. 24,- 1946. c.L. CUMMINS 2,408,298

' FUEL FEED ING AND INJECTION APPARATUS FOR OIL BURNiNG' ENGINES Filed April 26, 1945 9 Sheets-Sheet 5 INVENTOR. Cleaselfiznwzma m,,;4du m g I MM Sept. 24, 1946. c. L. CUMMINS 8,

FUEL FEEDINE AND INJECTION APPARATUS FOR OIL BURNING ENGINES I 9 Sheets-Sheet 4 Filed April 26 1943 M H/ i 0K uvmvrozc 'Clesszlsllimwubzs p 9 v c.-| cuMMms A 2,408,298

FUEL FEEDING AND "INJECTION APPARATUS FOR OIL BURNING ENGINES Filed April 26, 1943 9 sheets-shew 5 Sept. 24, 1946. Y I c. 1.. CUMMINS 2,403,293

FUEL FEEDING AND INJEGTION'APPARATUS FOR 0IL BURNING ENGINES Filed April 26-, 1945 9 Sheets-Sheet 6 :5 uwzurok. Cleasdaofl. 50mins Q ,BY "L Sept. 24, 1946. c; cdMmNs FUEL FEEDING AND INJECTION APYARATUS FOR OIL BURNING ENGINES Filed April 26, 1943 9 Sheets-Sheet '7 I h v 7 l l//////// a Sept. 24, 1946. c. L. CUMMINS FUEL FEEDING- INJEGTION APPARATUS FOR OIL BURNING ENGINES Filed April 26, 1943 9 Sheets-Sheet 8 Ail-El c. CUMMINS FUEL FEEDING AND INJECTION APPARATUS FOR OIL BURNING ENGINES Filed April 26. 1943 '9 Sheets-Sheet 9 1 Q. a 5 I a. 3 2

n Y m wllllrlllnnnri Patented Sept. 24, 1946 FUEL FEEDING AND INJECTION APPARATUS FOR OIL-BURNING ENGINES Clessie L. Cummins, Columbus, Ind., assignor to Cummins Engine Company, Inc., Columbus, Ind., a corporation of Indiana Application April 26, 1943, Serial No. 484,562

The present invention relates'to that type of fuel distributing and injection system which is characterized by the feeding of measured and equal charges of fuelat relatively low pressure to several injectors by a fuel measuring and-delivery device, and the discharge of such charges by the injectors into the engine cylinders against the much higher compression pressures pertaining therein. 7

The principal object of my present invention is to provide an improved'and simple fuel metering and delivery device in conjunction with the positive type of injectors, the metering and delivery device being common to all of the injectors, which of themselves act as positive valves in .affording distribution of the fuel charges in proper sequence to the several injectors and which are actuated to discharge the respective charges from the injectors into the combustion chambers of the engine cylinders. V I

Another object of my invention is toprovide a fuel feeding and injection apparatus in which each of the fuel injectors has a fuel charge space and an inlet port and a plunger for opening and closing the port and ejecting the fuel charge from the charge spaceinto the combustion space in the respective engine cylinder, the plungers being operated in predetermined order so that but one port is opened at a time, and in which apparatus a single fuel metering and. delivery device delivers fuel to a line common leading 'to said ports.

Another object of myinvention is to provide 2 Claims. (01. 123-139) a novel control device for alternatelyestablishing and disestablishing communication between means for feeding the fuel to. the metering and delivery device and also between the latter and the common line. 7

A further object of my invention is to provide a meteringand delivery device so that it serves a plurality of injectors and is positive in action and simple in construction.

The above and further objects of my invention will be set forth in the-following specification, reference being had to the accompanying drawings, and the novel means by which said objects are-effectuated will be definitely pointed out in the claims.

In the drawings:

Figure 1 is a side elevation of my improved metering and pump apparatus, including the governor;

Fig. 2 is a rear or right hand end elevation of th apparatus shown in Fig. 1; V

Fig. 3 is a vertical longitudinal section taken through the apparatus, along the line 3-3 of Fig. 2 and looking in the-direction of the arrows;

Fig. 4 is a horizontal section taken on-the line 4-4 of Fig. 3 and showing the gear pump for pumping fuel at low pressurefrom a supply tank into a float chamber;

Fig. 5 is a horizontal section taken on the line 5-5 of Fig. 3 and showing a gear pump for I drawing fuel from the float chamber; 7

Fig. 6 is a horizontal section through the apparatus, the section being taken on the line 66 of Fig. 3 and with some of the parts broken away;

Figs. 7 and 8 are horizontal sections through the lower part of the apparatus, the sections being taken on the lines 'I-'land 88, respectively, of Fig 2; V

Fig. 9 isa vertical section taken on the line 9- 9 of Fig.1; 1

Fig. 10 is a fragmentary horizontal section taken on the line Ill-l0 of Fig. 9; r

Fig. 11 is a vertical longitudinal sectio through the right hand side of the apparatus, the section being taken on the line ll-l| of Fig. 2;

Fig. 12 is a fragmentary vertical section taken on the line |'2-I 2 of Fig. 11;

Fig. 13 is another vertical section taken longitudinally through the apparatus on the line l3l3 of Fig. 2;

Fig. 13A is another vertical sectionon the line l3A-l3A of Fig. 2; I

Fig. 14 is a top plan view of the float chamber and float, with the float valve shown in section;

Figs. 15 and 16 are horizontal longitudinal sections through the metering and fuel charge device, the sections being taken, respectively, on lines l5-l5 and "3-46 of Fig. 1;

Fig. 17 is a vertical section, taken on the line ll-ll of Fig. 16;

Fig. 18 is a vertical section taken on the line |8-I8 of Fig. 16;

Fig. 19 is a schematic view of my improved fuel feeding and distributing system, with one of the fuel injectors shown diagrammatically.

Fig. 20 is a view showing one of the injectors in vertical section, the cam shaft for operating the injectors and the operating connections from one of the cams to the plunger of the injector illustrated, and

Fig. 21 is a somewhat diagrammatic front view of a l2-cylinder engine.

Referring first to Fig. 19, I have, by way of example only, schematically illustrated therein myinvention adapted for use in a six-cylinder four-cycle engine of the Cummins-Diesel type, though in otherfigures, I have shown the metering and pump apparatus as adapted for use on a twelve cylinder engine, as will be pointed out more fully later. In Figure 20 I have illustrated one of the injectors, which is designated generally by the numeral 25, the injector being also illustrated and more fully describedin my U. S. Letters Patent No. 2,199,915, granted February 13, 1949. In Figure 19 I have shown the lower portion of one of the injectors somewhat diagrammatically, and the injectors as being supplied with charges of fuel oil from a common line 23 through pipes at, one for each injector. The term fuel oil may be considered as embracing any suitabl liquid fuel.

Each injector has a body 26 suitably mounted chamber -29 formed in acup-shaped member 3 9 which is mounted on the lower end of the body and which has one or more ejection ports '31 con-- necting the chamber 2-9 with the combustion space of the cylinder. A spring 33, compressed between the top of the body and a head 34a on the upper end of the plunger, is compressed and tends to raise the plunger to its upper position, when allowed to do so by a cam 39, as shown in Figs. 19 and 2 0, and in which position a fuel port 3 5 is'uncovered by the cylindrical part of plunger. A charge of liquid fuel i fed past a check valve 35, through a passage 66 in the body, past a second check valve 3 and through the port 34 into the chamber 29, when th plunger is elevated, that is, when the port is uncovered. During a portion of the suction stroke of the piston in the engine the charge of fuel under pressure is forced into the chamber 2-9 by means to be described presently. During the compression stroke of the piston, air is driven from the combustion space into the mixing chamber 29 through the ports 3'! to mix and vaporize the oil. Shortly before the piston reaches top center on its compression stroke, the plunger is positively driven downwardly by the cam 39, through a pitman 4 9 and a rock lever M, to inject the entire mixture of fuel and air from the chamber into the-'combua tion space. -At the beginning of the downstroke of the plunger, it covers the port 3 3. The cams 39, there being one for each injector, aremounted on the cam shaft 42 which is driven from the main crankshaft d3 (Fig. 2 1 through suitable connections (not shown) at one-"half speed of the crankshaft. The cams are arranged on "the cam shaft so that only one plunger 2-! is fully raised and its port 34 uncovered at that time.

Thefuel system includes a 'low pressure gear pump for pumping the fuel oil from the source of supply into a float chamber, a higher pressure. gear pump for pumping oil from the float chamber into a metering and fuel delivery device which serves the injectors and forces a measured charge of fuel through the line 23 and the appropriate 'pipe 24 into the mixing chamber of the particular injector which has its port 34 uncovered by the plunger '2'! at the time.

me, which is designated generally by the numeral 34, has suitably journaled therein a cam shaft '45 (Fig. 3), on the forward end of which is keyed a sprocket driven from and in phase 4 with the crankshaft of the engine and at the same speed as the crankshaft. Through two meshing bevel gears 41, the shaft 45 rotates a vertical shaft '58 which, in turn, operates a low pressure gear pump 69 (Figs. 3, 4 and 19) and a higher pressure gear pump 59, (Figs. 3, 5 and 19). One gear of each pump is mounted on the shaft 8, and the pumps are separated by a plate 5!.

As best shown in Fig. 19, the gear pump 49 serves to pump the fuel from a supply tank (not shown), through a pipe 52, past a check valve '53, through a passage 54 to the pump, and then to discharge the fuel through a passage 55 into a float chamber 55. It will be observed that these passages (and other passages and ports to be mentioned) are shown in Figs. 3, 8, 11 and 13 and other as being drilled or otherwise formed in the walls of the casing itself, thus conserving space and eliminating the danger of breakage and leakage.

Mounted in the float chamber 55 (Figs. 3, 8, l4 and 19) is a float liiicontrolling a valve 59, in the usual way, to maintain a predetermined level of fuel in the chamber. Between the passages 54 and 55 is aconnecting by-pass passage 91, as best shown in Figs. 8, 9 and 19, in which is mounted a pressure control valve c2. When the valve 55 in the float chamber is closed, the fuel pumped by the pump $9 is circulated through this by-pass 5|, until the fuel level in the float chamber is lowered, permitting the valve 59 to open and more fuel to be admitted into the float chamber. At higher engine loads the valve 59 remains open because of the greater fuel consumption.

The higher pressure gear pump 50 draws the fuel from the float chamber through passages 64, and 65 (Figs. '7, 13 and 19) and discharges the oil through passages :38, 59 and 10, past a check valve H and through a strainer 12 into an enlarged passage 13 (Figs. 9, 10, 11 and 19). From a passage 13, which acts as the surge chamber to be described later, the oil is fed to the device Which meters and delivers a measured charge of oil through the line '23 (Fig. 19) into the mixing chamber of the particular injector having its port 34 uncovered. -A cross passage 14 connects the and apply the same reference numerals to the corresponding parts of the other with the suflix a added. The one device is designated generally by the letter M and the other by the letter M in Figs. 1, 3, 11, 13, 15 and 16, and the device M is schematically shown in Fig. 19. Reference will also be made to some details in Figs. 17 and 18. The two devices are mounted in solid metal blocks 19 and l9 forming part of the casing, the blocks being drilled to provide bores for the moving parts and also to form certain passages.

Slidably mounted in a vertical bore 61 (Figs, 3 and 18 in'particular) in the block 19 is a hollow slide valve 89 having two exterior annular grooves BI and 82. As best illustrated in Figs. 15, 1'7, 18 and 19, a passage-83 extends from the surge chamber 13 and terminates in the bore in which of'the valve and a cross bar 80'.

s the valve 80 ismounted. zThe end ofthe passage 83 forms a-port, designated by the reference numeral 84, which when the valve is in the position illustrated in the figures just mentioned, opens into the upper groo've'BI. A cam follower 9| (Figs. 3 and 18) in the lower end of the slide valve rests one cam 85 fast on the cam shaft 45. A spring 85 is compressed between the upper end Passages 81 and88 (Figs. 16 and 19) are formed in the lower 'en'd'of the block 19 and a plurality of ports 89 extend-from the passage 81 and open into the bore 61- in which the slide valve is mounted. A pipe 90 is connected to the outer end of the passage 88 and its other end is connected to the common line 23 for the fuel injectors. The slide valve '80, as will be described presently,- controls thepassage of oilto a metering and delivery pump and also controls the passage of the fuel, delivered by "this pump, through the pipe 90 to the common line 23 and the fuel injectors.

In the upper portions of the block M is a horizontal passage 92 (Figs. 15,- 18- and 19)"and a number of ports 93- connect one endof the passage with the bore 61 and, the; passage near its 'otherfend'leads to and from the" delivery pump. This pump will now be described, reference being made particularly to Figs. 3, 1'7 and 19. Fixedly secured in the upper end of another vertical bore '94 is the member 95 which is centrally bored and has a collar'or sleeve portion 95'extending into the bore 94. A piston 91 in the form of a sleeve is mounted'in the lower portion of the bore and has a cam follower I06 resting on a cam 99 fast on the shaft 45. A coil spring I is compressed between the lower sideof the block 19 and a flange on the lower end of the sleeve piston 91.

Slidably'mounted in the bore ofthe member ;95 and extending into the boreof the piston 91 is a metering sleeve'valve I02'which has an annular groove I03 -and ports I04 connecting the roovewit'h the central-bore of V the valve. "A coiled spring I05 is compressed between a flange on the member 95 and a flange on the upper e'nd '0 f the valve I02, the spring tending .j.

to'raise the valve, whose adjustment is controlled by a governor or; by hand, as will be described presently.

The passage 92 intersects the bore .94 providing. an oval shaped port I 01 (Figs. 13, 1'7 and 19) opening into the fuel chamber I08 between the lower end of the fixed sleeve 96 and the upper end of the delivery plunger 91. Extending downwardly from the central-portion'of the passage 921's an L'-shaped passage I09 (Figs. 13, 15, 18

and 19) which has a port I I0 opening into the annular groove 32 on the sleeve valve 80 The'governor for controlling the metering valve 102 is design atedgenerally by the reference letter "G (Figs. 1, 2, 3 and 6) and may be of any suitable design, the specificstructure forming'no part of my invention. As shown in Fig. 3 the main governor shaft I I3 is driven from the cam shaft :45 through oneof the beveledgears 41 and a beveled gear H4. The governor weight-levers II5 control the movement of asleeve I I6 and an arm '6 ported'in a recess of'the adjacent end of the shaft I2I. The shaft I2I'I has an eccentric portion I2I2 (Figs. 3 and 6) upon which is mounted a rocker lever I22, one end of which engages the upper end. of the metering valve I02. The inner end of the shaft I2I carries a projection ort'ang I2I3 which extends under and engages the other arm 'of the rocker lever I22. Mounted on the end of the shaft I2I I, which projects out of the casing, is an arm I and another arm I25 'is mounted on the projecting end of the shaft I2I I (Figs. '1; 2 and 6). The arms I25 and I25 are connected by a link I261. Mounted on the outer end of the shaft I2I is an arm I200 and arms I20 and I200 are connected by a link I26. The arm I25 has an upwardly projecting extension which is connected to the'hand throttle'control through suitable connections including a link or red I2'5I (Fig. 1). Through the mechanisms'described the governor and hand'throttle control effect adjustment of both 'metering'valves I02 and I02 at thesame time and tOJthG same extent.

- The speed; of the engine, and also of the governor,-increa ses as the engine load decreases. At such times, the governor-controlled shaft I2I rotates counterclockwise (Fig. 3) and with the hand-controlled shaft IZII and its eccentric I2I2 H1, in contact with a thrust bearing on the sleeve, moves a shaft H8 which is connected by -a -lin kII9 (Figs. 1. 2 and. 6) to an arm I20'fast on a short shaft I2I journaled in one of the side walls of the casing. A tension spring I21 (Fig.

stationary, the tang I2 I3 tends to move away from one end'of the rock lever I22, but the spring I05 raises its metering valve I02 progressively and maintains-thecontact between the lever and the tang. As the engine load increases the tang I2 I 3 rocks the lever I22 clockwise and lowers'the valve I02,- the spring I21 then overcoming thespring I as the speed of the governor decreases.

' It will also be apparent that: as the hand control, such as a foot throttle, is operated, the shaft .I2I-I and its eccentric I2I2 is adjustably' rotated clockwise as the footpedal is moved "toward full throttle position and counterclockwise upon reverse movement of thefoot' pedal. During this adjustment of the'eccentric, the tang I2I3 serves as a fulcrum for one end of the rock lever I22, the other end, and hence the metering valve I02, being lowered when the eccentric is turned clockwise, and being raised by the spring I05 when the eccentric is turned counterclockwise.

' The operation of the. structure embodying my invention as described above is as follows, referencebeing made more particularly to Figs. 3, 1'1, 18 and 19.

During operation of the engine, the low pressure gear pump 49 draws fuel from the source of supply and delivers it to the float chamber 56. The higher pressure gear pump 50 draws oil from the float chamber and discharges the oil through the passages 68, 69 and 10 into the enlarged passage or surge chamber 13. During the suction or "do-wnstroke ofthe delivery plunger 91 the ports metering valve I02 is controlled by the governor an d by the hand-control throttle. In Figures 3 "and 17 the valve I02 is shown in its lowermost 'orfu11' fuel position and the delivery plunger 91 is shown in its lowermost position with its upper edgejust above the upper edge of-thegroove 103 in .the valve Hi2. In 19 the delivery plunger .91 is shown in its lowermost position while the metering valve 102 is shown raised to its uppermost or no fuel position. ,As the valve is adjusted between its full fuel and "no fuel positions, more or less of its groove is in registry with the fuel space of the pump, or in other words, more or less of the groove )3 extends above the upper edge of the delivery plunger 91 when the latter is in its lowermost position. The fuel space fills up as the ports I04 in the valve 182 are smaller than the passages and ports through which the fuel is fed to the fuel space, and some of the oil so fed passes through the ports I64 to the central bore in the valve and then drops into the cam follower Hi6 and escapes through a hole in the follower back to the float chamber 56. Before the delivery plunger 91 begins to be raised by its cam 99, the cam 85 has raised the control valve 80 sufficiently to close the ports 93 and the ports 89 are then opened. The delivery plunger therefore forces some of the oil out of the fuel space I98 through the ports I04 in the metering valve l'02- until the plunger covers the groove 1-83 in this valve. Thus a measured or metered charge of fuel is trapped in the fuel space, the size of the charge being determined by the operating conditions of the engine. It will be understood, of course, that when the metering valve H32 is in its full load position, as illustrated in Figs. 3 and 17, none of the fuel in the fuel space 198 escapes through the groove "33 and ports -24 because the delivery plunger completely covers the groove and delivers a full charge of fuel.

The cam as for the delivery plunger, the cam 85 for the control valve $89 and the cams 39 for the injecting plungers 21 of the fuel injectors are in such timed or phased relation to each other and the main crankshaft that when the delivery plunger .9! is raised the'control valve 83 is also raised to cover the ports .93 and then uncover or open the ports 89 and only one of the injecting plungers 21 is fully elevated and the corresponding fuel inlet port 34 of the injector is opened, so that the measured quantity .of oil :in the fuel space I158 is forced through the port ml, the passage I09, the port Hill around the groove 132 of the control valve, through the ports .89, passages 81 and 3-8, and pipe 90 into the common line 23 from whence the metered charge of oil is discharged through the pipe 24 past the check. valves in the injector and through the. exposed port 3'4 into the mixing chamber 29 of the particular injector. Next the sliding valve fit! is lowered to close the ports 8.9 in order to prevent fuel from backing up into the delivery pump and then the injector plunger .21 is lowered and immediately covers the port 34 and then discharges the mixture of oil and air from the mixing chamber through the spray ports 31 .into the combustion space of the cylinders. The cams '85 and so permit the springs 86 and .Illii to lower the control valve 89 and delivery plungerii'l, respectively, the fuel space 1138 is again filled and the delivery plunger is raised again by the next lobe on its cam 99 to inject a charge of fuel into the mixing chamber of the injector for the cylinder next in the firing order of the engine and so on.

As already brought out, with the hand control eccentric l2l2 (Figs. 3 and 6) in fixed position, if theengine speed is reduced the governor spring 52! overcomes the spring l-tii of the metering valve Hi2 and lowers this valve toward full fuel position. This causes the engine to speed up, and

then the governor weights I15 overcome spring 1121., so that the valve I02 is permitted to be raised :by its spring 1.05,. This condition continues until an equilibrium is reached between the parts and the engine speed is held constant. Under hand throttle conditions, the eccentric l2l2 .is not fixed, so that even when the governor, upon reducing engine speed, calls for more fuel by rotating the rock lever I22 clockwise (Fig. 3), the hand control eccentric may be turned. counterclockwise to lift the right hand end of the lever and permit the spring to raise the valve 102, even though the fulcrum point (that isthe tang l2 l3.) has changed. The hand control eccentric is such that it may raise the valve to its no fuel position even when the governor calls for full fuel, and in this manner the engine may be brought to rest. The linkage is so set that it is impossible to force the control valve down further than a i predetermined point, which limits the load carrying ability -:of the engine and prevents overloading.

It will be observed that the cam shaft 42 carrying the cams 39 for operating the six injector plungers 21 is rotated at one-half crankshaft speed (through suitable gearing which is not shown) and that the shaft 45, carrying the threelobe cam 39 for the delivery pump and the threelobe cam 85 for the control valve 80 is rotated at crankshaft speed so that three of the injector plungers are operated during each rotation of the crankshaft and the metering and pumping device is likewise operated three times during each revolution of the crankshaft.

It will be observed that the control valve 80 and metering valve 182 float, that is to say, their free operation is not affected or impairedin any Way by oil pressure, as there is no oil pressure on eitherend of either valve and there is no side pressure against either valve, such as would press or bias the valve against the bore in which it operates. The passage 13 is enlarged to act as a surge chamber to minimize Or eliminate objectionable vibration which would otherwise result due to the fact that the fuel is intermittently fed ast the control valve'to the delivery pumpand the cut on and off at the ports $3 tend to caus pulsations in the line leading to the con trolvalve.

In each branch 24 (Fig. 19) from the common line 23 to the injectors is amanual shut-off valve 1313. In the event one :of the injectors has wholly or partially failed, the valves may be individually turned off and on during operation of the engine, and it can thus :be determined which of the injectors has failed by the action of the engine when each valve is closed.

If an injector fails or in cas one .of the valves i 36 is closed, the'oil pumped by the delivery pump would create too great a pressure between this pump and the injector or closed valve I30, and I therefore provide a relief ball valve I-3l (Figs. 13 and 19 connected into the passage 92, oil equal to the amount pumped by the delivery pump being forced past the spring pressed ball and dumped out of the upper open end of the valve casing 1-32 under the conditions stated.

Any oil leaking up between the injector plungers 2.! and the bores 28 of the injector bodies =escapes through ports 1134 (Figs. 19 and 2G). in the bodiesand passes through pipes I35 to a common line i31 leading back to the float chamber 56.

In a :12-cylinder engine, the other metering and de ivery unit M operates inthesame manner to deliver metered charges of .fuel to the mixing chambers of the injectors'for the other bank or group of six cylinders; The cams 85, 85 99, 59 and the cams 39 for operating the plungers 21 of the injectors are in such timed relation that the two metering and delivery devices are alternately operated and the injectors for the two groups of cylinders are also operated alternately.

I claim:

1. In a multi-cylinder, oil burning engine, a

plurality of injectors, one for each cylinder and each comprising a body having a fuel inlet port and a reciprocable plunger therein adapted when moved in one direction to leave a chamber in said body communicating with the associated cylinder and to open the inlet port, said chamber being adapted for mixing fuel and air, means for operating said injector plungers in predetermined order so that but one inlet port is opened at a time, a fuel line common to all of said ports, a fuel pump for delivering a controlled quantity of fuel to said line each time an inlet port is open and thereby forcing a like quantity of fuel from said line through said port to the associated chamber, said fuel pump acting to'so deliver fuel to each chamber in timed relation to movement of the piston in the associated cylinder that the piston thereafter forces air into the chamber to mix with the fuel therein, the plunger being timed to move thereafter in the opposite direc- 10 tion to close the port and to discharge the mixture of fuel and air from the chamber into the cylinder.

2. In a multi-cylinder, oil burning engine, a plurality of injectors, one foreach cylinder and each comprising a body having a fuel inlet port and a reciprocabie plunger therein adapted when moved in one direction to leave a chamber in said body communicating with the associated cylinder and to open the inlet port, said chamber being' adapted for mixing fuel and air, means for operating said injector plungers in predetermined order so that but one inlet port is opened at a time, a fuel lin common to all of said ports, a fuel pump, a single valve between said fuel line and fuel pump, said fuel pump delivering a controlled quantity of fuel through said valve to said line each time an inlet port is open and thereby forcing a like quantity of fuel from said line through said ort to the associated chamber, said fuel pump acting to so deliver fuel to each chamher in timed relation to movement of the piston in the associated cylinder that the piston thereafter forces air into the chamber to mix with the fuel therein, the plunger being timed to move thereafter in the opposite direction to close the port and to discharge the mixture of fuel and air from the chamber into the cylinder.

CLESSIE L. CUMMINS. 

